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D. E. PARK, H. AIKBN 8v H. W.'LASH. OPEN' HEARTH PURNAGE.

No. 365,936.. Patented Jul 5 1887.A

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NITED STATES PATENT rricn.

DAVID E. PARK, HENRY AIKEN, AND HORACE W. LASILOF PITTSBURG,

PENNSYLVANIA.

oPEN-HEARTH FURNACE.

SPECIFICATION forming pan; omettere Patent No. 365,936, dated July 5, 18er. Application filed Se; temher 14, 1885. Serial No. 176,989. (No model.)

To all whom. it may concern.'

Be it known that we, DAVID E. PARK, HENRY AIKEN, and Hennen W. LAsH, residing at Pittsburg, in the county of Allegheny and State of Pennsylvania, citizens of the United States, have invented or discovered certain new and useful Improvements in Open Hearth Furnaces, of which improvements the following is a specification.

part of this specification, Figure l is asec tional elevation of our improved furnace and.

plant for 'the production and casting of openhearth steel. Fig. 2 is a top plan View ofthe I5 Same.

In building furnaces for the production of open-hearth steel it is usually customary to arrange the regenerative chambers for heating the gas and air on the groundlcvel, and on zo these chambers, as a foundation or support,

the melting hearth and chamber is built. The

lines' for conducting the air and gas to the melting chamber are arranged alongside thereof, the Walls forming such iiues forming 2 5 part of the outer shell or wall of the meltingchamber and hearth. The brick walls between the fines and melting-chamber become highly heated, and'consequently are rapidly burned out, allowing the molten steel to escape 3o in the regenerative chambers; and this defect also exists in those furnaces where a slight airspace is left between the chamber and the lues, as such air-space does not extend for the full height of the melting-chamber. Another defect incident to .the usual arrangement of the open-hearth furnace arises from the height of the regenerative chambers, and the consequent necessity of lifting the metal charge te the charging-iioor--usually a height of ten or nro twelve feet-and the lowering of the molten metal to theingot-pit. A still further objectionable feature of -this construction is the fact that the furnace can be charged from ope side only, unless a movable platform is employed 4 5 an expedient seldom resorted to, as such platform would interfere with the movements ot' the ladle.

rlhe object of our invention is to so arrange and construct a furnace of the class described 5o as to permit of easy and ready access on all In the'accompanying drawings,wliich make Sides for the purpose of charging and repair; to so arrange the air-dues as to entirelyisolate the melting-chamber and hearth therefrom, except at such points where the fines enter the chamber, to permit of a full and free circulation of air around and under thev meltingchamber and hearth, thereby avoiding an excessive heating of the walls of the chamber and hearth, and consequently preventing the rapid burning out of such walls; to obviate 6o the hoisting ofthe materials charged into the furnace 5 to permit of the easy discharge of the molten metal into the ladle and its casting into ingots; and, finally, to avoid the use of stays and braces in the construction of the `6 5 furnace. 1

.To these ends our invention consists in the construction and combination substantially as hereinafter more fully described and claimed.

The shell of the hearth l is supported on a 7o series of I-beams, 2, which are supported at their ends by the side walls of the pit 3, sunk` a considerable distance below the level of the ground, as shown in Fig. l. The beams are ar ranged at such a distance below the groundlevel as to bring the charging-openings 4 ofthe hearth a convenient charging distance above the ground level. The pit 3 is rectangulariu shape, and is made of such size in proportion to the diameter ofthe hearth as to leave aeonsider- So able air-space between the Walls of the pit and the shell of the hearth. rihe hearth or melt` ing-chamber is formed by a shell consist-ing of a series of plates riveted together, lined with nre-brick, as shown in Fig. 2, and through the sides of the shellare formed a series of openings, through which the material can be charged into the hearth. These openings, which are closed by sliding doors 5, can be located at any point around the furnace, except in line with 9o theair-flues, and in any desired number, there by greatly increasing the facility in charging the furnace. rilhe cover or top 6 of the hearth is composed of fire-brick so arranged within a retaining ring or band, '7, as to form a con- 95 cavo-convex plate or disk, resting at its edge on the vertical wall of the hearth, with its convex sdeupward. As the briclcwork com posing the cover or top 6 is keyed or wedged within the retaining-band, the cover can be 10o e' estese built on the ground away from the hearth and then can be lifted by a suitable crane into place on the hearth and removed therefrom, if desired. By making the cover detachable it is possible to have an extra cover in readiness to be placed in position whenever the cover in use is destroyed or broken down, thus avoiding the delay now necessary' to permit the hearth cooling off before a new roof can be built, and in case it is necessary to repair the hearth itself the cover can be removed, thereby facilitating the cooling down of the hearth, and also permitting ready access to the damaged parts. In the center of the cover 6 is formed an opening, S, of larger capacity than the openings 4 in the side of the hearth,

for the admission of large pieces of .metall which cannot be broken up sufficiently small to pass through the openings 4. Over the opening 8 is placed the cover 9, provided with suitable hooks, whereby it may be lifted. On opposite sides of the pit 3 are built the horizontal ilues 10, which, extending some distance yunderground beyond the pit, converge vto a common chamber, 11, said chamber opening into the stack 12. These fluesl() are en lai-ged vertically at their ends adjacent to the chamber 12, forming chambers '13, their contiguous sides opening into what may be termed the air-pit 14. Over. the openings of. the fines and the chamber 13 into the chamberv 11v and air-pit 14 are arranged the verticallymovable valveplates 15, which are made of such a size as to cover only one of the open ings at the same time-as, for example, when the plates 15 are raised so as to close the openings from` the chamber 13 into the air-pit,

the openings from the tlues into the common chamber 11 will. be unobstructed.

Fromvthe furnace ends of the flues 10 eX- tend two or more vertical ilues, 16, which, passing along the sides of the hearth or melting-chamber, but at a distance therefrom, are connected at theirupper ends to the meltingchamber. by the horizontal lines 17, which enterthe melting-chamber through suitable openings in the top or cover 6. Through the wall of the hearth below the flues 17 are formed openings for the admission of gas, which is supplied through a system of pipes, 18, from any suitable source. The doors- 5 in froit of the openings 4 in the hearth are connected by chains or wire ropes 19, passing around suitably-arranged guide-pulleys to the operating levers 20,' pivoted on posts secured on a platform or pulpit located at one side of the furnace. between'the tap-hole 22 and the ladle-pit 23, located a short distance from the pit 8, and a suitable distance from the ladle-pit is located they ingot or casting pit 24. Between the ladle and casting pits is placed a hydraulic ladlecrane, 25, having a jibof such a sweep as tol permit of the ladle being moved from the la- Atrough or conductor, 21, is arranged admitted into the furnace through the system of pipes 18, and the valve-plates are so adjusted by raising one and lowering the other as to open communication between one of the iiues 10 and the stack through the chamber 11,

and close the opening of that ue andthe airpit; but the other flue is cut off from the stack, but is in communication with the air-pit through its vertical extension 13. While the valveplates are in the position stated air will enter the tlue in communication with the air. pit, and passing along such iiue will enter the hearth just above the gas-inlets, and combining with the gas will increase and accelerate the combustion of the latter. The products of combustion will escape through the iiue in communication with the stack, and vin their passage through such flue will highly heat' the walls thereof. As soon as the walls of the flue in communication with the stack arehighly heated throughout their entire length, by which time the walls of the other will be cooled 'down by the air passing therethrough, the position of the valve-plates 15 is reversed, so that the air will enter the hearth through the ilue previously heated by the products of coinbustion, which will now escape through the y opposite i'lue and heat its walls. The air as it passes along the heated ilues will be raised It is important that the air should.

IOO

rapidly; and this arrangement, in addition tov effect-ing thorough mixture of the air and gas, will also produce a downward deection of the burning gas onto the metal on the hearth, thus avoiding the necessity of curving the cover downward, as is now the usual practice.

The metal is charged into the hearthth rough l the openings 4, arranged around the furnace at such distances apart as to enable a gangof meu to work at each opening without interference with each other, thus providing for a more rapid charging than is possible in other forms of furnace. As soon as the metal has been properly treated the tap-hole is opened `and the molten metal tlows along the con- `ductor 21 into the ladle depending from the jib of the crane 25. As soon as all the metal has been run into the ladle the latter is raised and swung over the ingot-molds arranged in the pit 24. Itwill be understood that the gas is reversed, as is customary, at the same time that the air is l reversed.

It will be observed that all hoisting of the material to he charged is avoided in the above `construction of furnace, and that the material for the next charge can be placed in convenient position for charging onto the hearth while one charge is being .treated in the furnace. This preparation for charging is impracticable in the usual construction of openhearth furnaces, on account of the necessarily- IIO and another hearth placed in position.

seagsc y a old form of furnace be charged from more than one side, and then through only two or three doors at the most.

Another prominent characteristic of our furnace is the possibility of changing the hearth itself without the necessity of tearing down all of the airand gas'flues at the sides. When the hearth of our furnace needs renewal or repair,it is only necessary to remove a por-` tion of the horizontal flues 17, when the whole hearth can belifted from its supporting-beams In case of the burning through of the shell of the hearth, the escaping metal will run down into the pit 3 without causing any further injury to any other part of the furnace; but in the usual form of furnace the metal escaping from the hearth will run down into the checker-work in the regenerative chambers, thereby clogging them and rendering them useless. ifdesired, a sand pig bed may be made inthe bottom of the pit 3, thereby providing for molding of any escaping steel into convenient form for subsequent use. There is little liability, however, of the hearth being burned through, as it is entirely detached except where the air-'fines enter from other parts of the furnace, andthe air having ready access to all paris will rapidly carry off the radiant heat.

Another important feature of our invention is the accessibility of the tapping-hole and ladle from the ground, thus avoiding the necessity of swinging platforms and stages from which to reach either the tapping-hole of the hearth or the stopper-operating mechanism of the ladle. The hearth may be circular or slightly oval,as circumstances or the nature of the work to be performed may dictate.

This furnace is applicable not only to the production of steel, but may be used as a heating-*furnace or for any other metallurgie purpose. Y

XVe arcaware that a Siemens open-hearth furnace has been constructed with its chargngn doors accessible from the ground-level, its tapping-hole at or near the ground-level, and its regenerators underneath the hearth,and therefore'make no claim to such construction.

We claim herein as our invention-n l. An open-hearth furnace having its charging-doors accessible from the ground-.level, in combination with underground lines leading from opposite sides of the furnace and converging to a common stack, substantiall yas set forth g 2. An open-hearth furnacehaving its charging-doors accessible from the ground-level, its tapping-hole located at or near the groundlevel, in combination with underground fines leading from opposite sides ofthe furnace and converging to a common stack, substantially as set forth.

3. The combination of an open-hearth furnace circular in form and having its tappinghole at or near the ground-level, a ladle-pit located in convenient proximity to the tappinghole, a casting-pit located in convenient proximity to the ladle-pit, and a crane located between theladle and casting pits, substantially as set forth.

, 4. An open-hearth furnace, in combination with underground fines located on opposite sides of the hearth and converging to a common stack,airinlets connecting with the fines, and valves arranged to connect the lines alternately with the stack and with the air-inlets,\

substantially as set forth.

In testimony whereof we have hereunto set our hands.

DAVID E. PARK.' HENRY AIKEN. y HORACE W. LASH. NVitnesses':

DARWIN S. WoLcofrT, R. H. WHITTLEsEY. 

